In the field of wet processing, particularly that of treatment of printed circuit boards and industrial parts, the boards are often treated by wave soldering, etching, cleaning or the like, followed by various other treatments, generally including as a minimum, rinsing and drying. Similarly, in other types of treatments, such as electroplating or the like, the articles or items being plated are likewise followed by subsequent treatment steps, such as rinsing, drying and the like.
Frequently, the items being treated, whatever the form a treatment may take, will need to at least be rinsed and then dried, before subsequent processing or use can take place.
Often, the articles being treated have various thicknesses, such that the liquid treatment, such as rinsing or the like, and subsequent drying, must accommodate those various thicknesses of the articles being treated.
In some processing situations, such as when the printed circuit boards already have electronic components mounted on them, which electronic components are of various sizes and configurations, including, for example, resistors, capacitors, chips, transistors, plug-connectors, etc., such components themselves are of various thicknesses, such that when they are mounted on a printed circuit board, various portions of the boards with the components applied to them therefore assume various thicknesses within a given board. Similarly, from board-to-board, there can be considerable variation in thicknesses, because of variations in thicknesses of different components that appear on different ones of the boards.
Generally, such component-mounted boards undergo a treatment in the form of soldering, often of the wave soldering type, in which a large number of electrical connections of components on the boards are simultaneously soldered together.
It is most often necessary that following such a soldering operation, the boards need to be cleaned, generally by being rinsed and then dried, for removal of soldering flux, or of any other undesired substances from the boards.
Similarly, where other types of treatment are involved for boards, with or without electronic components on them, which treatments can take the form of etching, electroplating or the like, it is necessary to remove residues of the treatment process in a cleaning operation. Such cleaning operations will likewise involve rinsing, generally by means of a water rinse, followed by a drying operation.
Drying operations for following other rinsing or other operations are known in the art. Reference is made, for example, to the drying method and apparatus disclosed in U.S. Pat. No. 4,017,982, the complete disclosure of which is herein incorporated by reference. Such drying apparatus often involves the use of air knives that are fixedly mounted. It is, however, known in the art that often one of a pair of opposed air knives, often generally the upper air knife; namely that being disposed above the path of travel of printed circuit boards or other articles passing therebeneath, may be mounted, such that the ends of the air knife are carried by the apparatus in vertical slots, such that some raising of the air knife is facilitated when thicker articles are to be carried therepast. Also, it is noted that in some situations the mountings for an air knife at opposite ends, where they are carried by the apparatus, may be released, as being unbolted, with some tilting, pivoting or other modification or adjustment in the orientation of the air knife effected, followed by a re-bolting or affixing of the air knife back into a fixed position.